Multi-Stage Evaporator Cooling for Compressor-Free Data Center Racks
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cooling systems for data centers, such as those described in Japanese Patent Applications Laid-Open No. 2009-193244 and No. 2009-193137, face inefficiencies in heat exchange due to the use of large fin-and-tube evaporators and require external power sources like compressors, increasing energy consumption.
Innovation Solution
A cooling system with a multi-stage evaporator configuration, featuring upper and lower part headers and steam generating tubes, allows for efficient heat exchange with outside air without the need for a compressor, using a refrigerant like hydrofluoroether that boils at room temperature, and includes a flexible refrigerant pipe system and air blower for effective cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one large evaporator of a fin-and-tube type is used for a plurality of servers, then the structure is simplified, but the upper part of the tube in the evaporator is occupied by vaporized refrigerant and heat exchange cannot be performed efficiently
Solution Approach 1:
The evaporator is divided into multiple independent evaporator tubes instead of using one large evaporator. Each tube processes refrigerant separately, preventing vaporized refrigerant from occupying the upper part of a single large tube and blocking heat exchange. This segmentation maintains structural simplicity while restoring heat exchange efficiency.
2Loss of energy
If a plurality of fin-and-tube type evaporators are arranged between the rear door and electronic devices, then heat exchange capacity is increased, but an external power source such as a compressor is needed and electric power consumption increases
Solution Approach 1:
The system uses the heat from electronic devices themselves to drive the refrigeration cycle. The evaporators absorb heat directly from the electronic devices, and the refrigerant naturally circulates through phase change without requiring external power sources like compressors. This self-service approach increases heat exchange capacity while eliminating additional power consumption.
3Temperature
If a freezing cycle is used with multiple evaporators, then cooling capacity is increased, but electric power required for air conditioning of the data center increases due to need for compressor
Solution Approach 1:
The mechanical compression system is replaced with a phase-change-based refrigeration cycle. Instead of using a mechanical compressor to circulate refrigerant, the system relies on the natural phase change of refrigerant between liquid and vapor states to drive circulation. This substitution maintains cooling capacity while eliminating the need for powered compressors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables efficient heat exchange without a compressor, reducing energy consumption and improving cooling efficiency for electronic devices, while maintaining a compact size to minimize flow resistance and enhance thermal conductivity.
Implementation Method 1
an upper part evaporator, arranged between the upper part header and the middle header, including an upper part steam generating tube having a first flow path for leading a refrigerant of the middle header to the upper part header while making the refrigerant of the middle header perform heat exchange with outside air
Implementation Method 2
making the refrigerant of the middle header perform heat exchange with outside air
Implementation Method 3
a condensing unit installed in a place higher than the evaporator, and makes the refrigerant perform natural circulation using a difference in densities of the refrigerant in the vapor and liquid states
Implementation Method 4
a condenser for condensing a gas refrigerant into a liquid refrigerant by making a refrigerant and a cooling medium perform heat exchange with each other
Data Source
AI summary
A cooling system comprising: an evaporator for evaporating a refrigerant by performing heat exchange with outside air; a condenser for condensing a gas refrigerant into a liquid refrigerant by making a refrigerant and a cooling medium perform heat exchange with each other; a gas refrigerant pipe and a liquid refrigerant pipe connecting the evaporator and the condenser; and the evaporator including: an upper part header provided in a highest position of the evaporator, and connected with the condenser by the gas refrigerant pipe, through the gas refrigerant pipe a gas refrigerant flowing; a lower part header provided in a lowest position of the evaporator, and connected with the condenser by the liquid refrigerant pipe, through the liquid refrigerant pipe a liquid refrigerant flowing; a middle header provided in an intermediate position between the upper part header and the lower part header, and connected with the condenser by the liquid refrigerant pipe, through the liquid refrigerant pipe the liquid refrigerant flowing; an upper part evaporator, arranged between the upper part header and the middle header, including an upper part steam generating tube having a first flow path for leading a refrigerant of the middle header to the upper part header while making the refrigerant of the middle header perform heat exchange with outside air and having a second flow path for leading a refrigerant of the lower part header to the upper part header while making the refrigerant of the lower part header perform heat exchange with outside air; and a lower part evaporator, arranged between the lower part header and the middle header, including a lower part steam generating tube having a third flow path inserted into the middle header while making a refrigerant of the lower part header perform heat exchange with outside air, the lower part steam generating tube communicated with the second flow path of the upper part steam generating tube.